Hey @infotech, as Optus Loop is dependent on a broadband fixed connection - it can sometimes open up automatically just to let you know that its active and has been logged into it.
Just in case you weren't aware, you can Configure your Optus Loop settings
Should you have any inquiries and required some assistance to navigate through the feature, I would recommend having a chat to our Messenger teams whom will be able to look into your services and advise further. Our teams are available 24/7 via the Optus App
@infotechThere are number pf windows apps that allow you to disable / enable / delete apps that are configured to start on Windows startup and/or start schedules tasks and.or windows services. You can use one of these to disable the app or service (I do not know which type is is as I do not use it). One of the most common apps is called ccleaner (https://www.ccleaner.com/ccleaner/builds), which will allow you to disable it from starting. You will need to run it manually to start it once you disable it
The other option is to google hot to disable windows from automatically starting via the registry and edit the registry, but as you are asking I would NOT advise this as it's not for the faint hearted and you can cause allot of damage to windows if you screw things up in the registry.